A compact and lightweight zoom lens with high performance has been increasingly required for broadcasting and business purposes. Since high definition television broadcasting is about to proliferate, there is an urgent need for a zoom lens of practical size and weight which has high performance characteristics. Conventional zoom lenses often have many lens elements in order to attain a high performance, so they tend to be large and heavy. It has been difficult for these prior art lenses to maintain high performance imaging over the entire range of zoom from the wide-angle end to the telephoto end, while simultaneously allowing the subject distance to range from nearby to infinity. Thus, there is a need for a zoom lens which solves these two problems, while simultaneously providing a compact and lightweight zoom lens.
The assignee of the present invention has previously disclosed a zoom lens in Japanese Laid Open Patent Application H10-31157 in order to resolve these problems. However, a more lightweight and compact zoom lens is now required.